Hot-air furnace.



H. M. SAWRIE.

,HOT AIR FURNACE. APPLlCATiON FILED MAR. 9. 1914.

3 SHEETS-SHEET 1.

Patented Dec. 28,

H. M. SAWRIE.

HOT A| R FURNACE. APPLICATION HLED MAR. 9,- 1914.

Patented Dec. 28, 1915.

3 SHEETS-SHEET 2.

H. M. SAWRIE.

HOT AIR FURNACE.

APPLICATION FILED MAR. 9

atented Dec. 28,1915.

3 H EET 3.

3 SHEETS- STATlEg PATENT HEWLETT M. SAWRIE, OF NASHVILLE, TENNESSEE.

HOT-AIR FURNACE.

To all whom it may concern:

Be it lmown that I, HEWLETT M. SAWRIE, a citizen of the United States, residing at Nashville, in the county of Davidson and State of Tennessee, have invented a new and useful Improvement in Hot-Air Furnaces,

of which the following is a specification.

My invention relates to improvements warm air furnaces and the ob ect thereof is to construct a device provided with one or more flues whereby the products of combustion may be conducted thence by a circui-' tous path to give greater radiating surface to the furnace for the purpose of more 1ntensely heating the air inclosed by the furnace casing.

A. further object of 'my invention is to construct the off-take flues in such manner that the products of combustion from the combustion chamber will pass downwardly into the ashpit and be carried from thence laterally and upwardly by a circuitous path to the direct off-take flue of the .furnace.

With the foregoing and other objects in view my invention consists in the novel construction, combination and arrangement of parts constituting the invention to be hereinafter specifically described in theaccompanying drawings, which form a part hereof, wherein is shown the preferred embodiment of my invention, but it is to be under-- stood that changes, variations and modifications can be resorted to which come within the claims hereunto appended.

In" drawings hereto attached, in which similar reference letters indicate like parts in the different figures, Figure 1 is a perspective view of a furnace embodying my invention; Fig. 2 is a top-plan view, partly in section; Fig. 3 is a top view of graterest; Fig. 4 is a sectional view of Fig.3 on the line 44 Fig. 3; Fig. 5 is a view showing the manner in which the air circu-T lates when using the down-draft; Fig. 6 is a front view ofone of the rotatable gratecogs; Fig. 7 is a section of Fig. 6 on the line 77 Fig. 6; Fig. 8 is a perspective view of another style of modern furnace to which my system may be applied; Fig.9 is a front elevation of the ashpit door. v

In the plate 0 is mounted an ash door A, which leads to the ashpit H, between which and thefire-bowl N is located the R, which supports the grate-bars T.

grate-rest Specification of Letters Patent. pm md DMD 2g 9 1 15, Application filed March 9, 1914. Serial No. 823,392.

An upper smoke pipe C connects with an upper radiator B, which consists in an annular passage B communicating at the front of the furnace by a passageway B withthe dome B of the combustion chamber. A lower smoke pipe E, in line vertihaving its axis in line with the axis of the I damper C in the upper smoke pipe C, and so connected that it also is operated by the handle These two dampers are so arranged in relation to one another that when one is in a position to close the pipe within which it is located, the other is in a position to openthe pipe within which it is located. In the upper smoke pipe C, between the damper and the furnace, there is an open draft damper F of the ordinary type.

The upper radiator B,.located in the top .of the furnace, is an'annular chamber over the radiator J, opening into the combustion cham er, and having the clean-out opening and c lar G to which may be connected a pipe as hereinafter described.

Smoke-fines I lead from the ashpit H to the lower radiator J, which communicates with the top or upper smoke-pipe 0, through the lower smoke-pipe E .and' connection K. Surrounding the smoke-fines and radiators is a galvanized iron furnace casing L, between which anol the fire-bowl is the warmair chamber M.

The grate-rest R is hollow and consists of similar upper and lower portions which are suitably held together by bolts c as shown in Figs. 2, and 3. The grate-rest R has perforations r, to infuse .air into the smoke and gases passing down through the grate-bars T, thereby producing combustion and consumption of the gases and smoke, causing a reduction in the consumption of fuel. Graterest R is also provided on each side with sections of the grate-rest, as well as -form pivots by which grate-rest R can be dumped Each. grate-bar T is composed of a center i hollow or solid bar 6, eitherroundor square in cross-section, on which is mounted a series of cast-iron cogs, a (see Figs. 6 and 7 provided with teeth, 0, on their periphery. For the purpose of promoting more perfect combustion and also in order to prevent the cogs of the grate-bars becoming overheated air is allowed to enter the grate-bars through the air inlets S, and thence through the holes 03 in the cogs. .Each cog isprovided with a circular spacing sleeve, f, which serves to position the cogs with respect to each other and also to provide sufficient space for free circulation of air through the grate-bars. The air inlets S are attached rigidly to the grate-rest by means of the spacing sleeves or connections U. The ends of the center bars project through circular openings in the ash-door A, so they may be rotated by means of a suitable furnace wrench. The spacing sleeve on the cogs at each end of the gratebars engage circular recesses in the graterest and thereby rigidly hold the grate-bars in position. Cinders or clinkers are more readily broken up on their passage between the grate-bars by means of the teeth 0.

Since the cast-iron cogs a are solidly mounted upon the center bars b, they may be easily renewed should they become broken or burnt out.

In starting a fire in a furnace embodying my invention the damper handle D is preferably turned so as to permit the products of combustion from the fire-pot to pass directly upward into the upper radiator B and from thence outward through the upper smokepipe C to the chimney and this position of the damper, insuring this passage of the products of combustion, is maintained until the fire is effectually started. As soon as the fire has attained suflicient headway and it is desired to increase the radiation of heat from the furnace, the dampenhandle D is turned one-quarter of a revolution, thus obstructing the roducts of combustion through the upper smoke-pipe C and opening the damper in the lower pipe E The open draft damper F'is then turned, thus causing the products of combustion to pass downwardly through the grate into the ash pit and from thence through the smokeflues I to the lower radiator J, and thence through the lower smoke-pipe E through the connection K to the top smoke-pipe C. The same result can be accomplished by placing a rotary blower or air blast tube G in the clean-out collar G, thus forcing the air through the clean-out opening in upper radiator B -and downwardly through an elbow shaped pipe 9 connected with the cleanout'opening and extending down into the combustion chamber over the grate and into the ashpit as before.

.Fig. 8 shows an embodiment of my invention applied to another form of furnace,

having the upper smoke pipe C provided with the open draftidamper F and connected directly with the dome of the combustion chamber. From the ash pit H, smoke flues I extend upward to the smoke-box J located directly under the upper smoke pipe G at the rear of the furnace. The smoke-box J is connected with the lower smoke pipe E. In this second form of furnace, the draft is induced through the open draft damper F, in the upper smoke pipe C, the air pass- 'ing through the upper smoke pipe directly to the dome of the combustion chamber, thence through the furnace and out through the ash-pit H, through the smoke flues I and the smoke-box J to the lower smoke pipe E and connection K, to the upper smoke pipe C and the chimney.

I claim:

1. In a furnace of the character described, an upper smoke-pipe, a lower smoke-pipe connected thereto, a damper for simultanea ously closing the upper smoke-pipe and opening the-lower smoke-pipe, an upper and a lower radiator connected with the upper and lower smoke pipes respectively, the lower radiator provided with means of communication with the ash pit, and an open draft damper located in the upper smokepipe for forcing the products of combustion downwardly through the fire-bowl into the ashpit.

2. In a furnace of the character described an upper smoke-pipe, a lower smoke-pipe connected thereto, a damper for simultaneously closing the upper smoke-pipe and opening the lower smoke-pipe, an upper and a lower radiator connected with the upper and lower smoke-pipes respectively, smoke flues connecting the lower radiator with the ashpit, and means for forcing the products of I combustion downwardly through the grate into the ashpit and thence upwardly through the smoke-fines to the lower radiator.

3. A device comprising an 'upper and a lower radiator, connected with an upper and a lower smoke pipe respectively, the lower smoke pipe having connection with the upper smoke pipe, an ashpit, a hollow perforated grate-rest mounted above said ashpit, inlet air tubesconnected with ,said grate-rest, rota-table grate-bars comprising a center bar with a series of. toothed cogs having openings therein, mounted in 1' said grate-rest, .smoke fiues connecting the ashpit with the lower radiator, and means for forcing the products of combustion downwardly through the grate into the ashpit, thence upwardly through the smoke- I flues to the lower radiator and thence outwardly through thesmoke. pipes.

4. In a furnace, the combination of a com- 'bustion chamber; an ash-pit; two radiators communicating with the combustion cham- 1 her and ash-pit, respectively; direct and indirect draft pipes communicating with the two radiators, respectively; and with each other; and a damper mechanism for simultaneously closing one draft pipe and opening the other, or vice-verse; the direct draft pipe being provided with a damper-controlled air inlet between the damper mechanism and the combustion chamber; by means of which the furnace ma be operated 110 as an up-draft or adc n-dra furnace, at

will. v

. p HEWLETT M. sAWmE. Witnesses:

- f Wnmm P; DAVE,

'Tno 'As SAWRIE. 

